I am not sure what they're expectations of Ukraine are, maybe Ukraine is a victim of their own success in their offensives in Kyiv, Kharkiv and Kherson that they expect Ukraine to be able to defeat Russian forces overnight.
Ukraine has been shaping Crimea for years, slowly destroying AD (if Putin had enough AD then his refineries wouldn't be going boom), Putin's Black Sea fleet is removed from Crimea, soon they will logistically isolate it. This takes time. Ukraine will retake Crimea.
